Three categories of research comprise this project: development of myocardial perfusion techniques using quantitative, dynamic positron emission tomography; development of new PET flow tracers; and development of the instrumentation and reconstruction strategies for dynamic SPECT. This project embodies technology developments as well as tests of specific hypotheses. Specifically, we hypothesize that regional kinetic data on the wash-in of 82Rb will be given a more sensitive indication of segmental myocardial perfusion defects before and after coronary vasodilators that visual evaluations of static PET images. An evaluation of 125 patients is proposed, and they will receive quantitative angiographic assessment in collaboration with the Palo Alto VA, Stanford and University of California, San Francisco Medical Center. Related to this clinical trial is the hypothesis that the extraction of rubidium relative to flow is not seriously perturbed by ischemic heart disease, cardiac glycosides or insulin and glucose. Studies are planned in dogs and the red cell perfused rabbit heart model. Development and evaluation of 68Ga-complexes as convenient myocardial flow agents involves both chemical syntheses in collaboration with the University of Pennsylvania and animal verification studies against microspheres. The potential of dynamic SPECT using 5 second data acquisition times for the ventricular input function and subsequent quantitation of flow using attenuation-corrected reconstruction methods has been shown in preliminary studies. This project will pursue this methodology development with the University of Pennsylvania and University of Utah.